The antigenic structure of the polysaccharide component of gonococcal lipopolysaccharide is complex. Recent studies have indicated that rough (R) and smooth (S) gonococcal LPS variants exist and our own studies have substantiated the absence of LPS serotype antigens in R variants. The purpose of this proposal is to study R and S LPS variants from the six known LPS types to determine the chemical nature of the serotype determinants, the chemical and antigenic nature of the R polysaccharide, and the role of antibody to R polysaccharide in bactericidal systems. Using ferritin and peroxidase labelled monoclonal antibody developed in hybridomas as probes, the cell surface relationship of LPS determinants and POMP will be studied by transmission electron microscopy. The factors responsible for LPS polysaccharide degradation will be isolated, immunologically characterized and an immunoassay system developed to quantitate this material. Finally, conjugates of LPS-derived polysaccharide will be made with POMP and these materials will be studied for antigenicity, toxicity and immunogenicity.